With the increasing concern over the developing resistance of mosquitoes and other insects of medical importance to chemical pesticides, the use of baculoviruses as insecticides for integrated control represents a feasible alternative which is currently being developed. There is now an urgent need for a practical, rapid antigenic classification system for baculoviruses. This system would provide the methodology for quality control assessments of production products, for monitoring of the environment, for recognizing genetically induced antigenic changes in the virus, for detecting incorporated baculovirus antigens in cells of man or other non-target organisms, and for screening sera from individuals in high risk exposure situations for baculovirus-specific antibody. Baculoviruses will be grown in tissue culture and the resulting viral components will be purified, fractionated, and used to immunize animals. The antibody will be tested in the complement fixation, hemagglutination-inhibition, and plaque reduction neutralization tests to determine group and type-specific antigens. Porthetria dispar NPV grown in larvae and in tissue culture will be compared to confirm that no antigenic differences exist. A battery of reference antigens and antibody will be tested with field isolates of baculoviruses to establish the reliability and usefulness of the classification system.